Solid oxide fuel cells (SOFC) are of much interest due to their potential for high efficiency and fuel flexibility. SOFC generate electricity directly from an electrochemical reaction of fuels and oxidants. Unlike other types of fuel cells, SOFC's consist entirely of anhydrous solid-state components, such as an oxide electrolyte membrane that contains charged vacancies for oxide ion conduction and electrodes on both sides of the electrolyte membrane for current collection and catalysis. The SOFC reactions that represent reduction of oxygen into oxide ions at the cathodes and oxidation of oxide ions with fuel into water or other final products at the anodes mostly takes at or near contact boundaries between electrodes and electrolytes.
Typically, SOFC's operate at high temperatures. For example, temperatures between 700 and 1000° C. are useful for quick start-up and to reducing energy loss by electrical resistance through electrolytes or at the electrode-electrolyte boundaries. However, high temperature operation enhances breakdown of cell components. For this reason, there are efforts to reduce operation temperature. These efforts include engineering new materials used as fuel cell components, such as replacing yttria stabilized zirconia (YSZ), a typical electrolyte oxide of SOFC, with new materials such as samaria or gadolinia-doped ceria (SDC or GDC) that show higher oxide ion conductivity than YSZ's, or by replacing lanthanum strontium cobaltite ferrite (LSCF), a typical cathode of SOFC, with barium strontium cobaltite ferrite (BSCF) that shows lower electrolyte-electrode resistance.
Typically, SOFC electrodes use precious metal materials for catalysts such as platinum, ruthenium, palladium etc. These materials are very expensive and impact the overall fuel cell cost, which is very important for the commercialization of SOFC's. Desirable properties of these materials are good chemical stability and the ability to demonstrate high electrochemical activities i.e. high oxygen surface exchange rate.
Accordingly, there is a need to develop reduced cost solid oxide fuel cell having enhanced surface exchange rates and diffusivity of oxide ions.